import ( vld "github.com/tiendc/go-validator" ) type Person struct { FirstName string LastName string Birthdate time.Time Unemployed bool Salary uint Rank string WorkEmail string Projects []string TaskMap map[string]Task } var p Person errs := vld.Validate( // Validate first and last names separately vld.StrLen(&p.FirstName, 3, 30).OnError( vld.SetField("first_name", nil), vld.SetCustomKey("ERR_VLD_PERSON_FIRST_NAME_INVALID"), ), vld.StrLen(&p.FirstName, 3, 30).OnError( vld.SetField("last_name", nil), vld.SetCustomKey("ERR_VLD_PERSON_LAST_NAME_INVALID"), ), // OR use this to produce only one error when one of them fails vld.Group( vld.StrLen(&p.FirstName, 3, 30), vld.StrLen(&p.LastName, 3, 30), ).OnError( vld.SetField("name", nil), vld.SetCustomKey("ERR_VLD_PERSON_NAME_INVALID"), ), // Birthdate is optional, but when it's present, it must be within 1950 and now vld.When(!p.Birthdate.IsZero()).Then( vld.TimeRange(p.Birthdate, <1950-01-01>, time.Now()).OnError(...), ) vld.When(!p.Unemployed).Then( vld.Required(&p.Salary), // Work email must be valid vld.StrIsEmail(&p.WorkEmail), // Rank must be one of the constants vld.StrIn(&p.Rank, "Employee", "Manager", "Director"), vld.Case( vld.When(p.Rank == "Manager").Then(vld.NumGT(&p.Salary, 10000)), vld.When(p.Rank == "Director").Then(vld.NumGT(&p.Salary, 30000)), ).Default( vld.NumLT(&p.Salary, 10000), ), // Projects are optional, but when they are present, they must be unique and sorted vld.When(len(p.Projects) > 0).Then( vld.SliceUnique(p.Projects).OnError(...), vld.SliceSorted(p.Projects).OnError(...), ) ).Else( // When person is unemployed vld.NumEQ(&p.Salary, 0), vld.StrEQ(&p.WorkEmail, ""), ), // Validate slice elements vld.Slice(p.Projects).ForEach(func(elem int, index int, validator ItemValidator) { validator.Validate( vld.StrLen(&elem, 10, 30).OnError( vld.SetField(fmt.Sprintf("projects[%d]", index), nil), vld.SetCustomKey("ERR_VLD_PROJECT_NAME_INVALID"), ), ) }), // Validate map entries vld.Map(p.TaskMap).ForEach(func(k string, v Task, validator ItemValidator) { validator.Validate( vld.StrLen(&v.Name, 10, 30).OnError( vld.SetField(fmt.Sprintf("taskMap[%s].name", k), nil), vld.SetCustomKey("ERR_VLD_TASK_NAME_INVALID"), ), ) }), // OTHER FUNCTIONS // Pass if at least one of the validations passes vld.OneOf( // List of validations ), // Pass if exact one of the validations passes vld.ExactOneOf( // List of validations ), // Pass if none of the validations passes vld.NotOf( // List of validations ), ) for _, e := range errs { detail, warnErr := e.BuildDetail() fmt.Printf("%+v\n", detail) }

 errs := Validate( NumLTE(&p.Age, 40).OnError( // Override the default template in english SetTemplate("Tuổi nhân viên phải nhỏ hơn hoặc bằng {{.Max}}"), ), ) for _, e := range errs { detail, warnErr := e.BuildDetail() fmt.Printf("%+v\n", detail) }

 // Supposed you have 2 files defining error messages // In `error_messages.en`: // ERR_VLD_EMPLOYEE_AGE_TOO_BIG = "Employee {{.EmployeeName}} has age bigger than {{.Max}}" // In `error_messages.vi`: // ERR_VLD_EMPLOYEE_AGE_TOO_BIG = "Nhân viên {{.EmployeeName}} có tuổi lớn hơn {{.Max}}" errs := Validate( NumLTE(&p.Age, 40).OnError( // Custom param (the default template doesn't have this one) SetParam("EmployeeName", p.Name), // Custom key to define custom template to use SetCustomKey("ERR_VLD_EMPLOYEE_AGE_TOO_BIG"), ), ) for _, e := range errs { errKey := e.CustomKey() errParams : = e.Params() // or e.ParamsWithFormatter() errorMsg := translationFunction(errKey, errParams) // You need to provide this function fmt.Printf("%+v\n", errorMsg) }

 errs := Validate( NumLT(&budget, 1000000).OnError( SetField("Budget", nil), ), ) // e.BuildDetail() may produce message `Budget must be less than 1000000`, // but you may want a message like: `Budget must be less than 1,000,000`. // Let's use a custom formatter errs := Validate( NumLT(&budget, 1000000).OnError( SetField("Budget", nil), SetNumParamFormatter(NewDecimalFormatFunc('.', ',', "%f")), ), )